The future of web development is being shaped by three technologies: Ajax, Rich Internet Applications (RIAs), and Browsers. Studying the evolution of these technologies is critical to understanding the future of developing for the web, and close examination reveals the emerging trends that will define next generation web applications. How these technologies relate, how they compete, and how their evolution impacts web development is essential for developers planning any online application development.

The Impact of Ajax and Standards

When we talk about Ajax as a web technology, we're really talking about "standards-based" web development. Ajax is, after all, nothing more than a collection of familiar web standards -- JavaScript, the XmlHttpRequest (XHR) object, and structured data, like JSON and XML -- famously combined in to a simple pseudo-acronym by Jesse James Garrett in early 2005. For the last five years, Ajax has fuelled the "Web 2.0" explosion of interactive and rich Internet applications.

During this period, developers focused heavily on delivering "desktop-like" experiences through the browser in way that did not require users to install any additional software. Combined with an alphabet soup of standards, such as CSS, XHTML and RESTful web services, developers flooded the Web with interactive applications like Google Maps, Digg, and Zillow, and proved the standards-based Internet is a powerful platform for delivering applications.

The significance of standards is important. By choosing to use universally defined technology protocols, developers evolved a web that almost any Internet connected device with a browser can plug-in to. No proprietary software is required to run standards-based applications. You simply point your browser at an Ajax application and it works.

This simplicity is one of the biggest appeals of standards-based development. Unlike RIAs, it more or less guarantees users will be able to access your application.

Standards-based development and Ajax applications have critical limits, though. For example, there is no "standards-based" way to reliably play video in a web application today. JavaScript, the programming language of standards-based applications in the browser, is notoriously slow on its own, and as Ajax applications mature the speed of JavaScript is being pushed to its limits. And if you want to run an application "offline" when no Internet connection is available, today's standards have little to offer.
Fortunately, most of these problems are being addressed in the next version of HTML -- HTML5. The current drafts of the HTML5 standard propose solutions to the limits today's standards-based Ajax applications face, including:

Standard <video> and <audio> tags that make including rich media in a web page as easy as including an image.

Offline application APIs that enable developers to create offline accessible versions of their apps, and store and access data using client-side SQL.

Rich <canvas> APIs that make it possible to dynamically render 2D shapes and graphics directly in the browser.

Built-in APIs for dynamic tasks, such as drag-and-drop, that enable developers to use less JavaScript code to produce rich, standards-based applications.

According to the W3C, the consortium responsible for defining web standards, HTML5 aims to deliver solutions for many of the rich scenarios that plug-ins like Flash and Silverlight address today, but in an "open, vendor neutral languagewithout the risk of vendor lock-in."

If HTML5 is solving so many of today's standards "limits" and offering an experience on par with RIAs, why aren't Microsoft and Adobe fearful of this new standard? Doesn't HTML5 represent the death knell for Silverlight and Flash?

The downside of standards and the reason RIAs aren't fearful of HTML5 is that they evolve very slowly. The official "final draft" of the HTML5 standard is not scheduled for delivery until 2022! Assuming we're still writing applications for "web browsers" in that distant future, the pace of HTML5's evolution underscores the problem with standards. With no "horse in the race," the web standards groups have no motivation to move faster. They move slowly and deliberately, and at the end of the day, all they produce is guidance -- it's still up to browser manufacturers to interpret and implement the standards.

Fortunately, a "candidate recommendation" of the HTML5 spec will be released in 2012, and that's when many industry watchers expect to see widespread adoption of HTML5's features in the major browsers. But 2012 is three years out, and with major players like Apple and Nokia already balking at supporting a "universal" video codec, it's possible that some of HTML5's biggest features may be unusable in a true "cross-browser," standards-based way.

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This month's Dr. Dobb's Journal

This month,
Dr. Dobb's Journal is devoted to mobile programming. We introduce you to Apple's new Swift programming language, discuss the perils of being the third-most-popular mobile platform, revisit SQLite on Android
, and much more!